DIY Conductive Paint For All Your Wearable Needs

Conductive ink or paint is lots of fun. It opens up tons of possibilities for flexible and unique circuits — unfortunately, it’s pretty expensive. [Brian McEvoy] shows us how to make your own for cheap, and it works great!

He started trying to formulate his own recipe after playing with other Instructable guides and commercially available paint, and what he found is it’s really not that complex! Graphite powder, acrylic paint, and a jar with an airtight seal — seriously, it’s that simple! But, like any engineer worth their salt (he calls himself the 24 Hour Engineer), he had to do some tests to compare his formula.

In a detailed experiment he compares his formula to the commercially available Wire Glue, and two other recipes using Elmer’s Glue-All and graphite, and Titebond III with graphite. The results? Acrylic paint and graphite produce the most conductive material — and the cheapest!

NotArduino, you forgot :
compatable -> compatible
fartface might be forgiven if English isn’t his/her mother tongue.
Fact is native speakers tend to make more mistakes because they either don’t care or believe they are infallible (after all it’s their language).

Native speakers make mistakes…well, because they’re human, but also because they fundamentally think about the language differently from ESL people. Native speakers generally go off of what sounds fluid. Even people who know the grammatical rules in and out break them deliberately when it suits their purposes; they understand intuitively that the rules of grammar are descriptive and not prescriptive. Native speakers who *don’t* know the rules just eyeball it based on what “sounds right” when spoken, often literally/phonetically, which is how you get goofy, nonsense phrases like “could of” in place of “could’ve.”

You can do something similar with Nth Degree’s printable LEDs (I had a student who worked for them for a summer some years ago). Essentially LEDs that have contacts at each end – get them standing up with electrostatic force and sandwich them between (printed) conductive layers.http://youtu.be/yrrZ-A6VLqM

I really like this project, but I wish he was a little more systematic about drawing the traces. He measured with a repeatable length, but didn’t control for width or depth. Furthermore, a real analysis would include multiple traces with an examination of average and variance.

Regardless, it’s a good tip. I also shouldn’t complain about a project that was actually done and written up. Kudos to Brian McEvoy!

Perhaps even more important, it should be tested after a few flexural cycles, especially if he’s calling it “wearable”. I’ve made a few DIY conductive adhesives and it seems like conductivity vs. durability is always a compromise. With his apparently having high conductivity, I wouldn’t be surprised if it lacks severely in the other aspect.

Screen printing all the types onto the same piece of fabric at the same time could have worked for that and to ensure similar dimensions for the traces. Then cardboard back the fabric and bend it back and forth some number of times, tested, repeat.

I’ve been using model aircraft dope and graphite as grain filler for years, it gives a much nicer finish than talc, enamel “sticks” quite well.
As a bonus it seems to be good for shielding.
If you want some flexibility add some glycerine, a lot of texts say “a few drops”, but I’ve found if you put a “generous” amount of glycerine in, like a tablespoon in a 200 gram jar of dope, along with a few desert-spoons of graphite, 1 -> 2mm balsa ends up as flexible as ice cream container lid plastic and nearly as strong.
The resistance is gets a bit high, but if you are careful it is consistent.
The real bonus is it 1 -> 2mm sheet covering wing or fuselage surfaces will survive ass holes “testing” how hard they can press before they make a dent or a hole (yes, it has happened, damn coppers gave me a stern lecture on being “excessive” with my displeasure)

I guess it’s a case of ‘a few spoil it for the rest’. I’m not surprised by the knee-jerk reaction they’re having when people are posting videos of their quad-copters shooting fireworks or flying far away above a crowded city center and other craziness.

It depends on how much it flexes. As a patch it may work. The thick line of acrylic paint cracked when I bent the paper but the thin line held up. It seemed pretty brittle, like dry paint, go figure. The Titebond III flexed with no problem. The Glue-All acted about the same as the acrylic paint. So, if you’re doing a very small patch then Titebond III and graphite might be a good patch.

I once bought and tested the “wire glue” for a project – it was just a waste of time and money. It was bad in all aspects I could see or measure. Ended up with metal connectors for conduction and small epoxy dots for connection – which wasn’t a 100% fit for the project but worked reasonably well.
Bookmarked this article for future reference.